Miniaturized Wide-Band Baluns for RF Applications

ABSTRACT

A wide-band balun device includes a first metallization deposited over a substrate and oriented in a first coil. The first coil extends horizontally across the substrate while maintaining a substantially flat vertical profile. A second metallization is deposited over the substrate and oriented in a second coil. The second coil is magnetically coupled to the first coil and a portion of the second coil oriented interiorly of the first coil. A third metallization is deposited over the substrate and oriented in a third coil. The third coil is magnetically coupled to the first and second coils. A first portion of the third coil is oriented interiorly of the second coil. The third coil has a balanced port connected to the third coil between second and third portions of the third coil.

CLAIM TO DOMESTIC PRIORITY

The present application is a division of U.S. patent application Ser.No. 11/760,207, filed Jun. 8, 2007, and claims priority to the foregoingparent application pursuant to 35 U.S.C. §120.

FIELD OF THE INVENTION

The present invention relates in general to electronic devices and, moreparticularly, to compact balun structures used in wide-band radiofrequency (RF) applications.

BACKGROUND OF THE INVENTION

Electrical components, such as inductors, capacitors, computer chips,and the like, are increasingly in demand for a broad range ofapplications. Along with the increased overall need for thesecomponents, there is a drive to make the components more miniaturized insize and footprint. Smaller electrical components carry through tosmaller electrical devices, such as telephones and portable music playerdevices.

Electrical devices known as baluns are typically used to convertunbalanced electrical signals to balanced signals. A balun that operatesin a low frequency band and is used to connect a balanced transmissionline to an unbalanced line generally consists of a concentrated constantcomponent such as a transformer, whereas a balun that operates in ahigh-frequency microwave band consists of a distributed constantcomponent. Baluns known in the art consist of a distributed constantcomponent, including a quarter-wavelength matching element, or includetransformers having a size determined according to usable wavelengths.

Because baluns incorporating a distributed line topology necessarilyinclude the requirement of the length of the respective “line” to be inthe order of one-fourth of the wavelength at the operating frequency,line length requirements limit low frequency applications. Transformercharacteristics also limit allowable frequencies. As a result, a majordisadvantage to conventional balun designs is that respective frequencybands are fundamentally narrow.

A need exists for a balun device that realizes a compact design yet isusable in a wide band of frequency applications. The design wouldbenefit from compatibility with existing semiconductor technologies thatallow for integration of electrical components in semiconductor devices.

SUMMARY OF THE INVENTION

Accordingly, in one embodiment, the present invention is a wide-bandbalun device comprising a first coil formed over a substrate in a woundconfiguration extending horizontally across the substrate whilemaintaining a substantially flat vertical profile. A second coil isformed over the substrate in a wound configuration adjacent to the firstcoil. The second coil is magnetically coupled to the first coil. A thirdcoil is formed over the substrate in a wound configuration adjacent tothe second coil. The third coil is magnetically coupled to the secondcoil. The first, second, and third coils are arranged over the substrateas a single integrated structure.

In another embodiment, the present invention is a balun devicecomprising a first coil formed over a substrate in a wound configurationextending horizontally across the substrate. A second coil is formedover the substrate in a wound configuration adjacent to the first coil.The second coil is magnetically coupled to the first coil. The first andsecond coils are arranged over the substrate as a single integratedstructure.

In another embodiment, the present invention is a balun for asemiconductor device comprising a first metallization formed over asubstrate and patterned as a first coil extending horizontally acrossthe substrate. A second metallization is formed over the substrate andpatterned as a second coil adjacent to the first coil. The secondmetallization is magnetically coupled to the first metallization. Thefirst and second metallizations are arranged over the substrate as asingle integrated structure.

In another embodiment, the present invention is a method ofmanufacturing a balun comprising the steps of forming a firstmetallization over a substrate patterned as a first coil extendinghorizontally across the substrate, and forming a second metallizationover the substrate patterned as a second coil adjacent to the firstcoil. The second metallization is magnetically coupled to the firstmetallization. The method further includes the step of arranging thefirst and second metallizations over the substrate as a singleintegrated structure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary balun implementation;

FIG. 2A illustrates an exemplary prior art balun design incorporating adistributed constant component;

FIG. 2B illustrates a schematic diagram of an additional exemplary priorart balun implementation incorporating a capacitor device shunted toground;

FIG. 2C illustrates a schematic diagram of an additional exemplary priorart balun implementation incorporating loading capacitor devices;

FIG. 2D illustrates an additional exemplary prior art implementation ofa prior art balun design incorporating a distributed constant component;

FIG. 3 illustrates an exemplary coil structure;

FIG. 4 illustrates a schematic of an exemplary balun deviceincorporating a series of coil structures;

FIG. 5 illustrates an exemplary layout of a balun device incorporating aseries of coil structures and a plurality of capacitor devices depositedover a substrate;

FIG. 6 illustrates the layout depicted in FIG. 5 in a three-dimensionalview;

FIG. 7A illustrates an exemplary balun device incorporating a set oftwo-coils;

FIG. 7B illustrates a second exemplary balun device incorporating a setof three-coils;

FIG. 7C illustrates an electromagnetic response (EM) of a balun deviceincorporating a set of two-coils, and incorporating a set of threecoils, respectively to show a difference in insertion loss between thebalun devices;

FIG. 8 illustrates an electromagnetic response of the balun deviceincorporating a set of two-coils, and incorporating a set of threecoils, respectively, to show a difference in amplitude imbalance betweenthe balun devices;

FIG. 9 illustrates an electromagnetic response of the balun deviceincorporating a set of two-coils, and incorporating a set of threecoils, respectively to show a difference in phase imbalance between thebalun devices;

FIGS. 10A and 10B illustrate an exemplary coil structure, includingexemplary dimensions;

FIG. 11 illustrates an additional exemplary layout of a balun device,where a plurality of metallizations is integrated into a single coilstructure;

FIG. 12A illustrates an additional exemplary layout of a balun deviceincluding a plurality of magnetically coupled layers which can beintegrated using PCB or LTCC processes into a semiconductor device; and

FIG. 12B illustrates an additional view of the layered embodimentdepicted in FIG. 12A.

DETAILED DESCRIPTION OF THE DRAWINGS

The present invention is described in one or more embodiments in thefollowing description with reference to the Figures, in which likenumerals represent the same or similar elements. While the invention isdescribed in terms of the best mode for achieving the invention'sobjectives, it will be appreciated by those skilled in the art that itis intended to cover alternatives, modifications, and equivalents as maybe included within the spirit and scope of the invention as defined bythe appended claims and their equivalents as supported by the followingdisclosure and drawings.

Turning to FIG. 1, an exemplary balun implementation 10 for a wirelessdevice is depicted. The device includes an integrated circuit (IC)having a low noise amplifier (LNA) 14 associated with a receiver portionof the device. LNA 14 is coupled to matching circuits 16 and 18 for therespective legs of the LNA 14. Matching circuits 16 and 18 are coupledto balun device 20 as shown. Balun device 20 serves to convert anunbalanced input to a balanced output, as previously described. Balun 20is coupled to diplexer/switching device 22 to route input/output (I/O)signals through a filter device 24, and finally, to an antenna 26.

Similarly, incorporated into the transmitting portion of the device is apower amplifier (PA) device 28, which is also connected to a matchingcircuit 30 and 32 for each respective leg. The matching circuits 30 and32 are connected to balun 34. Again, balun 34 is coupled todiplexer/switcher 22, which is coupled through filter device 24 toantenna 26.

FIG. 2A illustrates an exemplary shunt transmission line balun device36. The balun device 36 is a three port device. An input 38, isconnected to a length of transmission “line” 40, and a second length oftransmission line 42, ending with an open circuit. Lines 46 and 48 arecoupled to ground 50 as shown, and coupled to output ports 52 and 54.Device 36 illustrates the conventional use of distributed constantcomponents, including quarter-wavelength matching elements (i.e., lines40 and 42). As previously described, the use of quarter-wavelengthelements have accompanying limitations in lower frequency applicationsdue to the physical constraints of the device requiring greater linelengths.

Turning to FIG. 2B, an additional exemplary schematic 56 of a balunimplementation 56 is shown in a so-called “transformer” implementation.Balun 56 includes an input port 58. A shunting capacitor 62 is coupledbetween ground 64 and node 60. A series capacitor is coupled betweennode 60 and a primary inductor coil 68 which is coupled to ground 70.Secondary inductor coil 72 is coupled to ground 74 at a center tap. Animpedance load (denoted Zbal) 76, such as a LNA 76, a PA 76, or asimilar active device 76 is connected across the secondary transformer72.

Similarly, in FIG. 2C, an additional exemplary schematic 78 of a balunimplementation 78 is shown in a structure similar to the implementation56 shown in FIG. 2B. Balun 78 again includes an input port 80 connectedto a series capacitor 82. Capacitor 82 is coupled to a primary inductorcoil 84 which is coupled to ground 86. The secondary inductor coil 88 isagain coupled to ground 90 at a center tap. Loading capacitors 92 and 94are coupled to each output of the secondary inductor coil 88, thecapacitors 92 and 94 coupled in parallel with the secondary winding 88.Output terminals of capacitors 92 and 94 are coupled to ground 96through node 98. Finally, an impedance load 100 (again, such as a LNA100, PA 100, or another similar active device 100) is placed in parallelwith winding 88, and capacitors 92 and 94 as shown.

FIG. 2D illustrates an additional balun design 102 utilizing distributedcomponents in a design similar to balun 36 shown in FIG. 2A. Balun 102includes a series of three sets of distributed line components which arecoupled together as shown. An input 104 includes an unbalanced port,coupled to distributed lines components 106 and 108. Components 106 and108 are coupled to components 110 and 112, which are each coupled toground 114 and 116 as shown. Components 118 and 120 are coupled toground 122 as shown at a first end. A second end of each component 118and 120 are coupled to terminals 124 and 126 of the balanced port.

As previously mentioned, transformer balun implementations such as balun56 and balun 78 in the prior art make wide-band implementationsunpractical due to physical characteristics of the transformercomponent. In light of the prior art, balun implementations can achievelimited wide-band functionality but at a cost of having a large size.Conversely, balun implementations can achieve a compact design andfootprint, but at a cost of drastically limited bandwidth.

As the exemplary implementation 10 in FIG. 1 indicates, a balun 20, orbalun 34 can be constructed according to the present invention, to beused in wide-band radio frequency (RF) applications such asimplementation 10. The baluns 20 and 34 can be used in RF applicationshaving a wide range of bandwidth (e.g., bandwidths of 800 MHz to 6 GHz),in contrast to the prior art. In one embodiment of the presentinvention, baluns 20 and 34 can be used in other, customer-requestedwide-band applications having bandwidths ranging from 800 MHz to 2100MHz. In further embodiments, ultra-wideband baluns (UWBs) can beconstructed.

In addition to having wide-band frequency characteristics, a balundevice 20 can be constructed, again according to the present invention,with an accompanying compact size and footprint.

A series of coil structures can be used for designs of integratedpassive devices (IPD), including those of baluns 20 and 34, that usesilicon and semiconductor technologies as will be described. Individualcoil structures can be combined into a series of integrated coilstructures. A series of coil structures can include three, four or moresingle coil structures, although three single coil structure designs canbe preferable in some cases for balun implementations as will be shown.The integrated coil structures form spiral inductor devices which aremagnetically coupled together. Beyond the inductive property from asingle coil structure, a series of integrated coil structures has anassociated mutual inductance which helps to realize a more compactdesign. In addition, the coil structures are efficient andcost-effective to manufacture.

Turning to FIG. 3, a conceptual diagram of a plurality of coilstructures 128 is shown. Three-coil structures are depicted, but again,four, five, or more coil structures can be realized in any givenimplementation. Coil structures 84, 86, and 88 are formed by depositingmetal tube-like structures over a substrate such as silicon or a similarmaterial.

The metal tube-like structures, or “tubes” can be arranged in the roundshape as shown. Additionally, the tubes can be configured in othergeometrical patterns, such as an octagonal geometrical design, to suit aparticular need. The tube structures can have a square, round, orrectangular cross section. In one embodiment, the tube structures arecomprised of a copper (Cu) or copper alloy metal material, althoughadditional metals and metal alloy materials can be utilized as required.The tubes can be deposited in a metallization process; accordingly, thetube structures can also be referred to as “metallizations.” The coilstructures 128 are magnetically coupled to each other. In general, themore bandwidth required for a particular application, the more coilstructures 128 can be utilized.

Coils 130, 132, and 134 include respective ends 142, 144, and 146 whichcan be adapted to provide an electrode-like function. Ends 142, 144, and146 can be positioned as shown.

Turning to FIG. 4, a schematic diagram of a balun device 150incorporating a plurality of coil structures is depicted. The device 150consists of four (4) capacitors and three (3) compact coil structures. Afirst capacitor (C1) is coupled between an input terminal 102constituting an unbalanced port 102 and an output terminal 155. A shuntcapacitor (C2) 156 is shunted between the terminal 155 and ground 158. Afirst coil is divided into two portions 160 and 161 as shown. Portion161 is coupled to ground 162. A second coil having portions 164 and 165is magnetically coupled to the first coil having portions 160 and 161.Portions 164 and 165 terminate at an open circuit. A center tap betweenthe portions 164 and 165 couples the portions 164 and 165 to ground 168.

A third capacitor (C3) 178 is coupled in parallel with portion 170 ofthe third coil and ground 182. The third coil is broken into twophysically separated portions 170 and 172 as shown. Portion 172terminates at node 176, where a first terminal 186 is coupled.Similarly, portion 170 terminates at node 174, where a second terminal188 is coupled. Terminals 186 and 188 collectively form a balanced port186 and 188 for the balun device 150.

In one embodiment, the capacitance of C1 is 4.0 picofarads (pF), whilethe capacitance of C2 is 1.2 picofarads (pF), and the capacitances of C3and C4 are 2.6 picofarads (pF). As one skilled in the art wouldanticipate, however, the various capacitances of the depicted capacitorscan be adjusted in any respect to suit a particular application andprovide an appropriate electrical response.

Three coupled coils are used to construct a wide-band balun, accordingto one embodiment of the present invention. Four matching capacitors C1,C2, C3, and C4 are used in the present example to compensate forparasitic capacitance from the physical layouts of the device 150. Therespective inductance of the coils and the capacitance of the matchingelements can be optimized, based on respective pass-band electricalrequirements.

FIG. 5 illustrates a balun device 150 incorporating an embodiment of thecoil structure of the present invention in a layout view. The varioussubcomponents depicted share the appropriate figure numbers from FIG. 4,including an unbalanced port 152, capacitor 154, capacitor 156, ground158 and 162, portion 164, portion 165, center tap 166, ground 168,portion 170, portion 172, capacitor 178, capacitor 180, and balancedport 186 and 188. A portion of second coil portion 165 is disposedinteriorly of third coil portion 172 as shown. Similarly, a portion offirst coil portion 161 is disposed interiorly to portions 165 and 172.Again, the coil portions 160, 164, and 170, as well as portions 161,165, and 172, are magnetically coupled.

Coil portions 160, 164, 170, 161, 165, and 172, as well as the variouscapacitors, leads, and ground structures are deposited over and extendhorizontally across a substrate, while maintaining a substantially flatvertical profile. The exemplary device 150 illustrated in FIG. 5 is awide-band balun device 150 operating at 1.5 GHz-2.2 GHz band, in oneembodiment. In another embodiment, the size of the device 150 isapproximately 1.6 mm×1.0 mm×0.25 mm in height, forming a small footprintand height. The use of round coil portions 160, 164, etc., is used inthe present example. A device 150 having the physical sizecharacteristics described constitutes a much smaller device thanconventional balun implementations as described in the prior art.

FIG. 6 illustrates the layout shown in FIG. 5 in a three-dimensionalview. Here again, the respective figure numbers from FIGS. 4 and 5 areshown. Unbalanced port 152, connecting leads to the various capacitors(e.g., capacitor 180), and unbalanced port with incorporated terminals186 and 188, are deposited over the substrate 192. Coil portions 160,164, 170, 161, 165, 172, grounds 168, 162, 168, and the variouscapacitor structures are deposited over the port terminals 162, 186, and188 and connecting leads. Coil portions 160, 164, 170, 161, 165, and 172extend horizontally across substrate 192 as shown. Here again, twogroups of three coupled coils are used. A series of wire bonding pads isadded for interconnection purposes.

As previously described, coil portions 160, 164, 170, 161, 165, and 172can form an inductive device which is consistent with other so-called“integrated passive devices” (IPD). A wide variety of the passivedevices such as a balun device consistent with the present invention,but also including resistors, capacitors, inductor or filter devices,transceivers, receivers, and other interconnects are placed on asubstrate such as substrate 192. The substrate 192 can include silicon,glass, laminate, or ceramic materials.

Integration of a balun device 150 using passive components depositedover a substrate 192 as described results in a high performance systemlevel solution, which provides a significant reduction in die size,weight, number of interconnections and system board space requirements,and can be used for many applications.

A wide variety of balun designs can be constructed which include coilportions 160, 164, 170, 161, 165, and 172 to suit particularapplications. The balun designs can be based on differing technologies,including silicon, printed circuit board (PCB) (laminate) or lowtemperature co-fired ceramic (LTCC) technologies. Again, as a result,substrate 192 can include materials such as silicon or silicon-likematerials, laminate materials, glass and ceramic materials.

Coil portions 160, 164, 170, 161, 165, and 172, as well as the overallbalun device 150 and accompanying subcomponentry, can be constructedusing materials, techniques, and manufacturing equipment known in theart, including various thin-film deposition methods and techniques andincorporating the use of known manufacturing tools and equipment.

Turning to FIG. 7A, a conceptual illustration of a balun device 196 isdepicted. Device 196 includes a set of two coils 199 and 201 which areorganized into a group of two-coil structures 198 and 200 as shown. Incomparison, FIG. 7B illustrates a conceptual depiction of a balun device202 having three coils 203, 205, and 207 which are also organized into agroup of two-coil structures 204 and 206. For the instant discussion,the balun device 196 is referred to as a “two-coil” balun 196 due to theuse of two coils 199 and 201 organized into the groups 198 and 200shown. Balun device 202 is referred to as a “three-coil” balun 202 dueto the use of three coils 203, 205, and 207, also organized into the twogroups 204 and 206 as shown.

An exemplary electromagnetic (EM) response curve which compares the twoand three-coil balun devices 196 and 202, respectively, is shown in FIG.7C. For the present figure, an insertion loss characteristic 208 iscompared between the two devices 196 and 202 across a specified range offrequencies 212. Frequencies 212 are measured and denoted in gigahertz,ranging from zero (0) to twelve (12) gigahertz. The difference ininsertion loss 210 is expressed as a percentage and denoted along theY-axis. Insertion loss is shown for device 196 as line 214. Similarly,loss is shown for device 202 as line 216. Various measurements 218 (m3),220 (m6), 222 (m7), and 224 (m9) confirm that the difference ininsertion loss between devices 196 and 202 is minimal (e.g., 1.5-1.7percent).

FIG. 8 illustrates a second exemplary EM response curve which comparesamplitude imbalance 226 of the two devices 196 and 202 across aspecified frequency range 230 (again denoted in GHz from 1.5 to 3.0 GHz)to illustrate a specific pass band range for a particular application.The two-coil balun device 196 is represented by line 232; the three-coilbalun device is represented by line 234. Relative amplitude 228 isdisplayed along the Y-axis in dB. Here again, various measurements 236(m10), 238 (m11), (m12), and (m13) are taken across the denotedfrequency range 230. The imbalance of the two-coil balun device 196exhibits markedly uneven amplitude, starting with approximately 1.30 dBat 1.5 GHz, which tapers but then increases. Conversely, the imbalanceof the three-coil balun device 202 is markedly less, beginning with0.067 dB at 1.5 GHz and continuing along a relatively linear path to0.327 dB at 2.2 GHz. The respective amplitude imbalance for thethree-coil balun 202 is generally less than 0.35 dB. Conversely, theamplitude imbalance for the two-coil balun 196 is greater than 1.35 dB.As a result, the three-coil balun device 202 exhibits wider bandwidthfunctionality and better amplitude balancing properties.

FIG. 9 illustrates a third exemplary EM response curve which comparesphase imbalance properties 244 of the two devices 196 and 202 across aspecified pass band range 248 (1.5 GHz to 2.2 GHz). Phase imbalance 246is measured in degrees and is shown along the Y-axis. Variousmeasurements 254 (m1), 256 (m2), 258 (m4), and 260 (m5) are denoted. Asone skilled in the art will realize, a balun device such as balun device202 should ideally exhibit a phase differential of 180 degrees fromunbalanced port to balanced port.

As shown, the phase imbalance of the two-coil balun device 196 isperceptively much greater than the three-coil balun device 202. For thetwo-coil device 196, phase imbalance is approximately 11 degrees acrossthe pass band range shown. Conversely, the three-coil device 202 has arespective phase imbalance of approximately 2.5 degrees across the passband range. As a result, the three-coil device 202 exhibits markedlybetter phase imbalance properties.

FIGS. 10A and 10B further illustrate the coil structures 128 in athree-dimensional view. Again, coils 130, 132, and 134, havingelectrodes 142, 144, and 146. FIG. 9B illustrates various dimensionalaspects 262 of coil structure 130, including height (H) 263, width (W)268, coil spacing (S) 264, and inner opening diameter (d) 266.

When an electromagnetic wave interacts with a conductive material,mobile charges within the material are made to oscillate back and forthwith the same frequency as the impinging fields. The movement of thesecharges, usually electrons, constitutes an alternating electric current,the magnitude of which is greatest at the conductor's surface. Thedecline in current density versus depth is known as the “skin effect.”

So-called “skin depth” is a measure of the distance over which thecurrent falls to 1/e of its original value. A gradual change in phaseaccompanies the change in magnitude, so that, at a given time and atappropriate depths, the current can be flowing in the opposite directionto that at the surface.

The skin depth is a property of the material that varies with thefrequency of the applied wave. A respective skin depth can be calculatedfrom the relative permittivity and conductivity of the material andfrequency of the wave. First, the material's complex permittivity, c isfound such that

$\begin{matrix}{ɛ_{c} = {ɛ( {1 - {j\frac{\sigma}{\omega \; ɛ}}} )}} & (1)\end{matrix}$

where:

ε=permittivity of the material of propagation,

ω=angular frequency of the wave, and

σ=electrical conductivity of the material of propagation.

In one embodiment, to overcome the skin effect and minimize metal loss,a respective thickness of the coil structures 130, 132, and 134 ismaintained to be larger than the respective skin depth.

Again, in one embodiment, copper (Cu) is utilized as a metal materialfor coil 130. A thickness of eight (8) micrometers exceeds the skindepth for copper (taking into account the electrical conductivity of thecopper metal). A thickness greater than five (5) micrometers isrecommended, with, again, a preferable thickness of eight (8)micrometers.

The total length of coil 130 is related to the operating frequency ofcoil 130. In one embodiment, the coil width 268 is twenty (20)micrometers. The coil height 263 is also eight (8) micrometers. The coilspacing 264 is seventy (70) micrometers. The number of turns (T) is two(2). The inner opening diameter 266 is 220 micrometers. Total area isapproximately 0.65×0.65=0.42 mm². The estimated inductance for the coil130 is estimated to be approximately 2.0 nanohenrys (nH) at operatingfrequency 2.2 gigahertz (GHz).

Again, as one skilled in the art would anticipate, the variousdimensions of coil 130, as well as coils 132, and 134, such as width 268and space 264 can be optimized using tools such as a computer program tosuit differing footprint requirements and/or differing specificationrequirements.

FIG. 11 illustrates an additional embodiment of a balun device 270 wherethe various coil structures are integrated and deposited over asubstrate in a single group or single configuration as shown. Here, asin FIG. 5, an unbalanced port 272 is configured as shown, and coupled toa first capacitor 274 and a second capacitor 276, which is shunted to aground pad 280. Coils 282, 284, and 288 are deposited and configured asa single integrated group. A portion of coil 284 lies interior to coil282. Similarly, a portion of coil 288 lies interior to coil 284.

A portion of coil 284 is left as an open circuit, terminating atlocation 286 as shown. A portion of coil 288 is coupled to a thirdcapacitor 294 and a fourth capacitor 290, which are both coupled to aground pad 296 as shown. A first output terminal pad 292 of a balancedport is coupled to capacitor 290 as shown. Similarly, a second outputterminal pad 298 is coupled to capacitor 294 as shown.

Turning to FIGS. 12A and 12B, an additional, multi-layered embodiment ofa coil portion 300 of a balun device is depicted. As FIG. 12Aillustrates, three coupled coils 302, 304 and 306 are multi-layered anddeposited over a substrate (not shown). Structures 308 are integratedinto each of the coils 302, 304, 306 to connect a top layer, forexample, of the coil 302 with a bottom layer of the coil 302.

Various technologies such as printed circuit board (PCB) or lowtemperature co-fired ceramic (LTCC) processes can be implemented to formthe layered coil structures 300, as one skilled in the art would expect.FIG. 12B illustrates the layered coil structures 300 in a second view308.

As FIGS. 12A and 12B indicate, in one embodiment, the layering of thevarious coils can be configured such that a portion of coil 306 isdisposed and/or oriented between a portion of a layer portion of coil302 and a layer portion of coil 304. Here, as before, the coils can thenbe connected to other supporting components, such as a balanced portpads (not shown) and capacitor devices, which can also be integrated andconfigured to coincide with the various layer components of the coils300. For example, the balanced port pads can be connected to the thirdcoil between portions of the third coil, in a manner similar to thatdepicted in FIG. 5 or 11. A substrate (not shown), over which the coils300 are disposed, can again include a silicon, glass, or ceramicsubstrate for structural support. The coil structures 300 can comprise aportion of a larger overall semiconductor device.

In addition to implementing PCB and LTCC technologies in fabricationprocesses for coils 300, various structural and packaging technologiessuch as overmolding compounds and encapsulants can be used to provideadditional structural support to the orientation of coils 300, and alsosupport additional discrete components which are integrated over thesubstrate. Again, various configurations and specifications for thevarious components can be implemented to suit a particular application.For example, the compact coils 300 can be joined to matching capacitorswhich have been configured in a variety of series and/or shuntconfigurations.

Coil structures such as coils 302, 304, and 306 in implementationscombined with capacitors such as capacitors 294, connecting leads andbonding pads such as ground pad 280, which are all deposited over asubstrate as previously depicted, can provide wide-band balunfunctionality in a dramatically decreased size and footprint. While oneor more embodiments of the present invention have been illustrated indetail, the skilled artisan will appreciate that modifications andadaptations to those embodiments may be made without departing from thescope of the present invention as set forth in the following claims.

1. A wide-band balun device, comprising: a first coil formed over asubstrate in a wound configuration extending horizontally across thesubstrate while maintaining a substantially flat vertical profile; asecond coil formed over the substrate in a wound configuration adjacentto the first coil, the second coil being magnetically coupled to thefirst coil; and a third coil formed over the substrate in a woundconfiguration adjacent to the second coil, the third coil beingmagnetically coupled to the second coil, wherein the first, second, andthird coils are arranged over the substrate as a single integratedstructure.
 2. The wide-band balun device of claim 1, wherein thesubstrate is made with silicon, glass, or ceramic material forstructural support.
 3. The wide-band balun device of claim 1, whereinthe first, second, and third coils have a rectangular cross-section. 4.The wide-band balun device of claim 1, wherein the first, second, andthird coils include copper or a copper alloy material.
 5. The wide-bandbalun device of claim 1, further including a semiconductor devicecontaining the first, second, and third coils.
 6. A balun device,comprising: a first coil formed over a substrate in a woundconfiguration extending horizontally across the substrate; and a secondcoil formed over the substrate in a wound configuration adjacent to thefirst coil, the second coil being magnetically coupled to the firstcoil, wherein the first and second coils are arranged over the substrateas a single integrated structure.
 7. The balun device of claim 6,further including a third coil formed over the substrate in a woundconfiguration adjacent to the second coil, the third coil beingmagnetically coupled to the second coil.
 8. The balun device of claim 7,wherein the first, second, and third coils are arranged over thesubstrate as a single integrated structure.
 9. The balun device of claim6, further including a semiconductor device containing the group of twocoil structures.
 10. The balun device of claim 6, wherein the substrateis made with silicon, glass, or ceramic material for structural support.11. The balun device of claim 6, wherein the first and second coils havea rectangular cross-section or round cross-section.
 12. A balun for asemiconductor device, comprising: a first metallization formed over asubstrate and patterned as a first coil extending horizontally acrossthe substrate; and a second metallization formed over the substrate andpatterned as a second coil adjacent to the first coil, the secondmetallization being magnetically coupled to the first metallization,wherein the first and second metallizations are arranged over thesubstrate as a single integrated structure.
 13. The balun of claim 12,further including a third metallization formed over the substrate andpatterned as a third coil adjacent to the second coil, the thirdmetallization being magnetically coupled to the second metallization.14. The balun of claim 13, wherein the first, second, and thirdmetallizations are arranged over the substrate as a single integratedstructure.
 15. The balun of claim 12, wherein the substrate is made withsilicon, glass, or ceramic material for structural support.
 16. Thebalun of claim 12, wherein the first, second, and third coils includecopper or a copper alloy material.
 17. The balun of claim 12, whereinthe first and second metallizations have a rectangular or roundcross-section.
 18. A method of manufacturing a balun, comprising:forming a first metallization over a substrate patterned as a first coilextending horizontally across the substrate; forming a secondmetallization over the substrate patterned as a second coil adjacent tothe first coil, the second metallization being magnetically coupled tothe first metallization; and arranging the first and secondmetallizations over the substrate as a single integrated structure. 19.The method of claim 18, further including forming a third metallizationover the substrate patterned as a third coil adjacent to the secondcoil, the third metallization being magnetically coupled to the secondmetallization.
 20. The method of claim 19, further including arrangingthe first, second, and third metallizations over the substrate as asingle integrated structure.
 21. The method of claim 18, wherein thefirst and second coils include copper or a copper alloy material. 22.The method of claim 18, wherein the first and second metallizations havea rectangular cross-section or round cross-section.
 23. The method ofclaim 18, wherein the substrate is made with silicon, glass, or ceramicmaterial for structural support.
 24. The method of claim 18, furtherincluding forming the first, second, and third metallizations on asemiconductor device.